COOLING FAN SYSTEM Cooling Fan Circuit

DESCRIPTION

The ECM calculates an appropriate cooling fan speed based on the engine coolant temperature, inverter coolant temperature, air conditioning switch condition, refrigerant pressure, engine speed and vehicle speed, and sends the signals to the cooling fan ECU to regulate the cooling fan. The cooling fan ECU controls the cooling fan speed based on the duty ratio signal sent from the ECM. By basing its control on the operating conditions, the ECM can control the fan speed optimally using the cooling fan ECU, achieving both high cooling performance and quietness.

WIRING DIAGRAM

Refer to System Diagram Click here.

CAUTION / NOTICE / HINT

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. PERFORM ACTIVE TEST USING GTS (CONTROL THE ELECTRIC COOLING FAN)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Electric Cooling Fan.

    5. Check the operation of the cooling fan while operating them using the GTS.

      OK
      Tester Operation Specified Condition
      ON Cooling fan operating
      OFF Cooling fan stopped
      Result
      Result Proceed to
      OK A
      NG (Cooling fan does not operate) B
      NG (Cooling fan does not stop) C

    A

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    C

    CHECK HARNESS AND CONNECTOR (ECM - COOLING FAN ECU) Click here

    B

  2. INSPECT COOLING FAN MOTOR


    1. Inspect the cooling fan motor Click here.


    NG

    REPLACE COOLING FAN MOTOR Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU POWER SOURCE)


    1. A01V1JVE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Cooling Fan ECU)

      Disconnect the cooling fan ECU connector.

    2. Turn the ignition switch to ON (IG).

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      A35-1 (+B1) - A35-3 (E1) Ignition switch ON (IG) 11 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (COOLING FAN ECU - BODY GROUND) Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (ECM - COOLING FAN ECU)


    1. Disconnect the ECM connector.

    2. Disconnect the cooling fan ECU connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A28-45 (RFC) or A35-2 (SI) - Body ground Always 10 kΩ or higher

    OK

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - COOLING FAN ECU)

  5. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU - BODY GROUND)


    1. Disconnect the cooling fan ECU connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A35-3 (E1) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU - BODY GROUND)

    OK

  6. INSPECT COOLING FAN RELAY (FAN RELAY)


    1. Inspect the FAN relay Click here.


    NG

    REPLACE COOLING FAN RELAY (FAN RELAY)

    OK

  7. CHECK HARNESS AND CONNECTOR (FAN RELAY POWER SOURCE)


    1. A01UZZPE01
      Text in Illustration
      *1 No. 2 Engine Room Relay Block and No. 2 Junction Block Assembly
      *2 FAN Relay

      Remove the FAN relay from the No. 2 engine room relay block and No. 2 junction block assembly.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      3 (FAN relay) - Body ground Ignition switch off 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN RELAY - AUXILIARY BATTERY)

    OK

  8. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU - FAN RELAY)


    1. Remove the FAN relay from the No. 2 engine room relay block and No. 2 junction block assembly.

    2. Disconnect the cooling fan ECU connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A35-1 (+B1) - 5 (FAN relay) Always Below 1 Ω
      A35-1 (+B1) or 5 (FAN relay) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU - FAN RELAY)

    OK

  9. CHECK HARNESS AND CONNECTOR (FAN RELAY - BODY GROUND)


    1. Remove the FAN relay from the No. 2 engine room relay block and No. 2 junction block assembly.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 (FAN relay) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN RELAY - BODY GROUND)

    OK

  10. CHECK HARNESS AND CONNECTOR (FAN RELAY - NO. 1 INTEGRATION RELAY)


    1. Remove the FAN relay from the No. 2 engine room relay block and No. 2 junction block assembly.

    2. Disconnect the No. 1 integration relay connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      1(FAN relay) - 2C-4 Always Below 1 Ω
      1(FAN relay) or 2C-4 - Body ground Always 10 kΩ or higher

    OK

    CHECK ECM POWER SOURCE CIRCUIT Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN RELAY - NO. 1 INTEGRATION RELAY)

  11. CHECK HARNESS AND CONNECTOR (ECM - COOLING FAN ECU)


    1. Disconnect the ECM connector.

    2. Disconnect the cooling fan ECU connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A28-45 (RFC) - A35-2 (SI) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - COOLING FAN ECU)

    OK

  12. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR - BODY GROUND)


    1. A01UYCBE02
      Text in Illustration
      *a

      Component without harness connected

      (Cooling Fan Motor)

      Disconnect the cooling fan motor connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      z6-1 (-) - Body ground Always 10 kΩ or higher

    OK

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    NG

    REPLACE COOLING FAN MOTOR Click here